Advancements in the semiconductor industry have enabled the integration of billions of transistors on a single semiconductor. Typically, however, only a fraction of the transistors operate at full voltage or frequency, for example, in order not to exceed the thermal design power (TDP) of the semiconductor. Often, a large number of circuit blocks are either inactive (e.g., dark silicon) or in a reduced-power state (e.g., dim silicon) at any given time to satisfy power and thermal constraints.
Circuits typically enter a reduced power state when the workload is light to save power and reduce the cost of cooling. However, on-chip voltage regulators operate indifferently under varying workload conditions and generally provide optimum efficiency for only a certain amount of output power. Since dynamically changing the design parameters of a voltage regulator under different workloads can be relatively difficult, existing power management techniques suffer from increased voltage conversion losses during idle states when current demand is low.
Another growing concern is the security of information processed or stored in integrated circuits (ICs). Several techniques are used by attackers to obtain secret information or functionality from ICs. For example, a side channel power attack is one non-invasive technique to obtain secret information or identify secret functionality of an IC. In such an attack, the correlation between stored information (or functionality) and the power consumption of the IC is exploited. Various input combinations are typically applied to the IC by an attacker. The correlation among the power consumption profiles for different input patterns is statistically analyzed to solve the secret key or learn the secret functionality.